I have been meaning to fix this up for a long time, but so far real
work keeps getting in the way. The idea is that C-C t brings you to
this week's time tracker buffer, and then you use (C-c C-x C-i/C-c C-x
C-o) to start and stop timers.

The only even slightly clever is stopping the timer and saving on
quitting emacs, which I borrowed from the someone on the net.